German patent publication 100 29 138 A1 discloses a use block for an electric tool which has a read unit in the form of a transmission and receiving unit in the housing of the work apparatus. The transmission and receiving unit communicates with a transponder carried by a user. For an unauthorized taking into service, there is an intervention in the work apparatus by means of a safety circuit in such a manner that the motor cannot be taken into operation.
If such an apparatus needs servicing, the transfer of the personal transponder of the user to the service facility is regularly necessary. Only then is the service technician in the position to take the work apparatus into service.
Basically, it is also known to use master transponders which are usable as master keys for an entire group of apparatus. If one master transponder of this type is stolen, the use block of a plurality of apparatus is useless.